This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to confirm that free plasma cortisol fractionated by temperature controlled ultrafiltration and measured by immunochemiluminescence is highly correlated with free cortisol fractionated by equilibrium dialysis and measured by immunochemiluminescence. Examine single nucleotide polymorphisms (SNPs) in genes within the cortisol biosynthesis in response to stress as a proof of principle pilot investigation.